[Hormesis and stress responses of human cells to chemical and physical hazards present at work places].

Such a phenomenon when very low doses of harmful chemical or physical agent make the cell "ready" to remain completely indifferent to higher doses of this agent is called hormesis, and factors which evoke this phenomenon--hormetic factors. The majority of hormetic factors are also stress to cells. This suggests that cell mechanisms evoked by hormetic and stress factors are similar. Among occurrence which accompany the cell hormesis and stress, polypeptides called "stress" and "shock" proteins play an important role. Proteins synthesized in conditions of thermal shock, so called proteins of thermal shock (Hsp) are especially well known. Proteins of Hsp70 and Hsp90 families as well as ubiquitin belong to the same group. Proteins of thermal shock are indispensable for protecting cells against a destructive effect of exogenous chemical and physical agents. Understanding of mechanisms associated with cell hormesis and stress is of great importance for occupational medicine. It has been found out that exposure, especially to low doses of harmful factor, does not always produce adverse health effects in an exposed organism.